Speed responsive device with automatic fluid pressure modifier



24, 1951 c. L. 'MUZZEY ETAL 2,561,588

SPEED RESPONSIVE DEVICE WITH AUTOMATIC FLUID PRESSURE MODIFIER Filed May 4, 1946 4 Sheets-Sheet 1 c. L. MUZZEY ETAL 2,561,588 SPEED RESPONSIVE DEVICE WITH AUTOMATIC FLUID PRESSURE MODIFIER Filed May 4, 1946 4 Sheets-Sheet '2 July 24, 1951 Z63 m 160 3 4. W

I J 1 L290 Jyr jgvgrwoas ATTORNEYS y 24, 1951 c. L. MUZZEY ETAL 2,551,533

spasm RESPONSIVE mavxcs WITH AUTOMATIC FLUID PRESSURE MODIFIER Filed May 4, 1946 4 Sheets -Sheet 3 zo'l INVENTORiv 32/ I 27a 52,10. way Mr;

3 ATTORNEYS July 24, 1951 Filed May 4, 1946 c. L. MUZZEY ETAL 2,561,588 SPEED RESPONSIVE DEVICE WITH AUTOMATIC FLUID PRESSURE MODIFIER 4 Sheets-Sheet 4 'A/m-A/roes Patented July 24, 1951 SPEED RESPONSIVE o MATIC FLUID PRE Clifford L. Muney, Dayton, Carson, Cambridge, Mass.,

Motors Corporation, tion of Delaware EVICE wrrn auro- SSURE MODIFIER Ohio, and Howard assignors to General Detroit, Micln, a corpora- Applicatlon May 4, 1946, Serial No. 667,314

9 Claims. (Cl. 264-7) This invention relates to governors for controlling the speed of a prime mover by controlling the medium which operates it.

An object of the present invention is to provide an improved governor having stability of control.

In the disclosed embodiment of the invention this object is accomplished by the use of an hydraulic servo whose piston is connected by a piston rod with a throttle valve or other device which controls the flow of operating medium to the prime mover. The rod side of the piston is subjected to a substantially constant pressure and the other side of the piston, larger in area than the rod side, is subjected to a total pressure which is greater or less than the total pressure on the rod side depending on underspeed or overspeed. The rate of flow of pressure flow into or out of the space in the servo cylinder at the piston side of larger area is caused to be proportional to speed error and to the rate of change of speed error by virtue of the operation of valve connected with said space and operating to control flow rate in proportion to speed error and by virtue of operation ofa stabilizer having a cylinder which is connected at one end with said space and having a piston whose rate of displacement is caused to be proportional to the rate of change of speed error.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a perspective view of governor embodying the invention.

Figs. 2 and 3 are diagrams of fluid passages of the governor.

Fig. 4' is a vertical, longitudinal, sectional view on line 44 of Fig. 8, of a governor shown in Fig. 1.

Fig. 5 is a sectional view on line 5--5 of Fig. 4.

Fig. 6 is a sectional view on line 66 of Fig. 7.

Figs. 7 and 8 are sectional views taken, respectively, on lines 'I-l and 8-8 of Fig. 4.

Fig. 9 is a sectional view on line 9-9 of Fig. 8.

Fig. 10 is a sectional view on line I8-I8 of Fig. 7.

Fig. 11 is a sectional view on line II-II of Fig. 7.

Fig. 12 is an hydraulic circuit diagram of the governor.

Referring to Fig. 1, the governor unit comprises a base I15, a housing I'IG supported by the base, and the cover I" supported by the housing.-

Referring to Fig. 4, the base is attached by screws I18 to the frame I19 of the engine which drives a shaft I88. Shaft I8I, splinedly connected with shaft I88, is journaled in a bushing I82 supported by the housing I16. Since the housing contains hydraulic fluid, the upper surface of the base is provided with a flat surface I83 engaged by a neoprene seal ring I85 carried by a bushing I 84 through which the shaft I8I extends. A spring I86 confined between the lower end of bushing I82 and the upper'end of bushing I84 urges the latter and the ring I85 against the surface I83. Shaft I8I has a spiral groove I8Ia for receiving oil leaking pastthe top of bushing I 84. The lead of groove I8Ia. is such that it tends to elevate the oil and return it to the reservoir while the shaft IBI is rotated.

Shaft I8I is integral with a gear I81 meshing with a gear I88 provided with a bearing sleeve I 8! rotatably supported by a sleeve I88 fixed to the housing I18. Sleeve I88 is retained by a plate I9I (see Fig. 7) attached to the housing by screws I92. Gear I88 provides a plate I83 providing lugs I94 to which rivets I85 attach leaf spring hinges I98 to which rivets I 81 and I 88 attach a stiffening plate I98 and an additional weight 288. Two rivets I98 also connect the upper ends of the hinged plate I96 to a strap I. The two branches of strap 28! pass through notches 282 in the flange of a dish-like disc 283 which is attached to a valve 285 having lands 286 and 281. The upper end of valve 285 is press-fitted into the inner race of a ball bearing 288, the outer race of which is press-fitted into a cup 289 which receives the lower end of governor control. spring 2I8, the upper end of which receives a plug 2 connected by a. pin III with a lever III. The forked right end (Fig. 8) of lever M3 is attached by pins 2" to a nut 2I5 through which a screw 2I8 is threaded, said screw being supported by an extension of housing I16. By turning the screw 2I6. the nut IIS and the fulcrum pins 2 are raised and lowered for purposes of adjustment. The screw 2 I8 is retained in adjusted position by a bushing 2" having (attached to frame I18 by screws Illa) a radially serrated flange 2 I! of screw 2I5. when screw 2I6 is turned, it is carried downwardly by reason of the coaction of the serration, downward movement being resisted by spring 2I8 which urges the screw 2I8 upwardly to reengage the serrations after the screw has been adjusted.

The adjustment ofv fulcrum pin 2 provides for adjustment of the left end of lever III relative to a cam 228 which operatw the lever. Cam 2" (Fig. 8) is attached to a shaft 22| supported with a tubular shaft 222 not connected therewith and by a bearing 223 attachedto the housing. Shaft 22I is provided with a groove 224 receiving a screw pin 225 in order that the shaft 22I will be retained in position. Shaft 22I is connected with a lever 226 providing a socket 221 for receiving a spring 228 bearing against the flange 229 of a rod 238 having a knurled head 23 I. As shown in Fig. 1, the rod 23I is adapted to be received by any one of a series of holes 232 located upon an arcuate centerline concentric with the axis of shaft 22 I. Each of the holes 232 represent a particular speed for which thegovernor is set. The cam 228 is located between spacer sleeves 234 and 235. Since'at least a part of the governor is immersed in hydraulic fluid it is desirable to prevent churning of the fluid by the governor as much as possible. To minimize churning or foaming, the governor is enclosed by a sheet metal like shroud 236 secured to the plate I93 by screws 231 and nuts 238.

Valve 285 is received by a sleeve valve 248 which provides ports 2 connected with annular groove 242 communicating with ports 243 connected with groove 244 of sleeve I98. Land 281 of valve 285 controls ports 241 and 248 of valve 248 connected with annular groove 249 always connected with ports 258 of sleeve I98 connected with annular groove 25I of said sleeve. A valve guide sleeve 268 (Figs. 6 and 11) is received by bore 26I in the housing I16 and retained therein by a plate I9I which is shaped to fit into an annular groove 262 of the sleeve 268. Sleeve 268 receives a valve 263 having lands 264 and 265. Land 265 controls ports 266 and 261. Ports 266 and 261 in sleeve 268 are connected with annular groove 268. Sleeve 260 provides holes 269 connected with annular groove 269'.

s A stabilizer cylinder 218 (Fig. 4) is received by a socket 2" of housing I16 and sealed by ring 212. Cylinder 218 is provided with an internal groove 213 connected by holes 214 with the interior of the cylinder. The upper end of the cylinder is closed by a cap 215 sealed by ring 216. Cylinder 218 receives a piston 211 connected with a rod 218. The piston rod 218 is connected by a lever 219 with a cam 288 having a slot 28I which receives a pin 282 fixed to a bar 283 having a notch 284 (Fig. which receives the cam 288. The bar 283 is adjustable horizontally in Fig. 5. For this purpose it is provided with screw threads 285 engaged by a nut 286 having a flange 281 b which screws 288 may attach it to the housing I16. By removing the screws 288, the nut 28!; can be turned upon the screw 285, thus making an adjustment of the position of the bar 283 when the nut 288 is again attached to the housing. In this manner the relation of the pin 282 to the slot 28| of the cam 288 can be changed thereby changing the eccentricity of the cam 288 relative to the pin 282. As shown in Fig. 4 the pin 282 is substantially concentric relative to the contour of the cam 288. By adjusting the rod 283, the amount of movement transmitted from the piston 218 by the cam 288 to a cam follower plate 298 can be varied. Adjustment of pin 282 relative to piston rod 218 and valve 248 changes the ratio of the lever arms of these parts with respect to the pin and changes the degree of stabilization or stabilization sensitivity constant of the stabilizer which includes the piston 211. Cam follower plate 298 (Fig. 5) provides a hole 29I for loosely receiving a pin 292 attached to the housing. A pin 293 passes through a washer 294 retained by 4 pin 295 and then through a spring 296 and then through the plate 298 and then into the housing. The spring 296 serves to maintain the plate in contact with fulcrum studs 291 and 298 carried .by the housing. The plate 298 is caused to follow the cam 288 by reason of engagement of valve 248 with plate 298 said valve being urged downwardly by leaf spring 388 (Fig. 4). Therefore the spring 388 forces the plate 298 down against cam 288 while the spring 296 urges the plate 299 against the fulcrum studs 291 and 298. In this way movement of piston rod 218 effects movements of the valve 248 and the plate 298 which ,rocks about a line V-W (Fig. 5) which crosses the ends of the studs 291 and 298. As shown in Fig. 6, plate 298 is engaged by valve 263 which is urged downwardly by spring 263a. The amount of motion imparted by the plate 298 to the valve 263 will depend on the amount of movement imparted by the cam 288 to the plate 298 and also will depend on the perpendicular distance from the center line of valve 263 to the line V-W (Fig. 5). The throw of the valve 263 can be changed by changing the position of the fulcrum stud 298, for example, to the position 298'. In such case, the plate would rock on the line XY, Fig. 5. Because the basic time constant of the governor is a function of the ratio of the lever arms of valve 263 and cam 288 with respect to the fulcrum represented by line V-W or line XY, change in location of the fulcrum will cause a change in the basic time constant. This change can be made without changing the degree of stabilization or the stabilization sensitivity constant of the stabilizer. For the purpose of this adjustment, the housing would be provided with a plurality of holes, each for receiving the stud 298.

Gear I88, Figs. 4, '7 and 6 drives a gear 388 which operates a pressure pump P comprising gears 38I and 382 driven by gear 388 and confined in a housing provided by plates 383, 384 and 3850 This housing provides an inlet 386 connected with the hydraulic fluid within the housing I16. Plate 385 provides an outlet 381 connected by a passage 388 in housing I18 with a cylindrical bore 389 therein which receives a sleeve 3I8 retained in the bore 389 by a plate 3 attached to the housing I16 by screws 3I2. The sleeve provides a groove 3I3 connected with a reservoir in the housing, said groove being connected by ports 3I4 with a cylinder 3I5 provided by the sleeve. said cylinder receiving a piston 3I6 having a rod 3", the upper end of which terminates in a notched dashpot disc 3I8. Between the sleeve 3I8 and the disc 3I8 is located a spring 3I9, tending to urge the piston valve 3I6 up to close the ports 3I4. When oil pressure in the bore 389 and cylinder 3I5 exceeds a certain amount, the piston 3I6 which serves as a pressure control valve moves down to open the ports 3I4 and thus limits the pressure in passage 388 and also in the passage 328 connected with the bore 389.

Referring to Fig. 10, a cylinder 32I is received bya socket 322 provided by the housing. Cylinder 32I receives a piston 323 having a rod 324 which extends through a cover 325. Rod 324 carries a pin 326, Fig. 9, received by notches 321 in the arms 328 of a lever 329 connected by a key 333 with shaft 22.2. Shaft 222 is supported by a bearing 33I in the housing I16 and is connected with a lever 332 by which the connection may be made to the engine throttle. In order that this :8 connection may be be adjustable, lever 332 is provided with a slot for receiving a pin not shown, which can be located at different distances from the axis of the shaft 222.

The various ducts connecting the pump valves and cylinders will now be (explained particularly with reference to Figs. 2 and 3. The bore 308 in housing I16 connects with pump outlet 301. Bore 308 is connected by bore 340 with bore 34I Fig. 4, receiving a filter 342 having a flange 343 attached to the housing I16 by screws 343a. The interior of the filter is connected by bore 344 with the bore I90 which receives the sleeve I90 of Fig. 4. Bore 345 connects bore I80 with the bore 250' which receives the sleeve 260 of valve unit 0. Groove 25I of sleeve I90 (Fig. 4), is connected by a bore 346 connected with a bore 341 connected with a vertical bore 348 (Fig. 10), connected with a passage 349 in cap or cover 215, said passage leading to the upper end of cylinder 210. Groove 268 of unit (Fig. 11), is connected with bore 350 connected with a bore 35I (Fig. 2) connected with bore 352 (Fig. in alignment with hole 353 of cylinder 32I, said cylinder having a hole 354 in a ignment with a bore 355 (continuation of 352). Bore 355 is connected with groove 213 of cylinder 210, connected with the lower end of the cylinder through passages 214. The pump is connected with the upper end of cylinder 32I through bores 308 and 308 (Fig. 2), bore 308, bore 320, bore 356, vertical bore 351 (Fig. 10) and passages 358 in cover 325 leading to the upper end of cylinder 32!.

In Fig. 12, pipe 356 represents the chain of ducts (Fig. 2) 358, 351, 356, 320, 300', 308 which connect the upper end of cylinder 32I (Fig. 10) with the pump P (Fig. 6). In Fig. 12, pipe 344 represents the chain of ducts 308, 340, filter 342, ducts 344, 345 (Fig. 2) connecting the pump P and the valve sleeve 260. In Fig. 12, pipe 35I represents the chain of ducts 353, 352, 35I (Fig. 10) and 350 (Fig. 2) connecting the lower end of cylinder 32I with groove 2'28 (Fig. 11) of valve sleeve 260. Pipe 345 represents duct 345 (Fig. 11) connecting groove 269' of sleeve 260 with groove 244 of sleeve I90. In Fig. 12, pipe 341 connecting groove 25I with the upper end of cylinder 210 represents ducts 345, 341 (Fig. 11) and ducts 341, 348 and 349 (Figs. 2 and 10).

When the governed speed is being maintained. the pistons 211 and 323 of cylinders 210 and 32I are substantially stationary. There will be of course minute vibration of the valves 205 and 263, thereby providing enough leakage of pressure fluid around the valve lands and through ports to provide the pressures required to hold the pistons 211 and 323 substantially stationary. A practically constant pressure is applied to the upper side of piston 323 through pipe 356. When there is equilibrium, piston 323 is balanced between the pressures above and below; and the piston 211 is balanced between the pressures above and below it. By relieving the pressure above piston 211, the pressure below piston 323 is relieved. Pressure below the piston 323 can be relieved also by bleeding the pipe 35I. Thus by two routes fluid can escape from the lower end of cylinder 32I. In consequence, piston 323 descends as piston 211 ascends and as fluid escapes from pipe 35I at port 266. Conversely by causing pressure above piston 211 to increase and overbalance the pressure below the piston, piston 211 moves down to force fluid through the pipe 355 to increase the pressure below piston 323. Pressure below piston 323 may be increased also by causing a flow through pipe 35I into cylinder 32I. Thus two routes or paths are provided for causing flow of fluid into the bottom piston 323.

In case of underspeed error, valve 205 moves downwardly to uncover port 241 whereupon flow of pressure fluid from pump P into the upper end of cylinder 210 causes the piston 211 to move down and the piston 323 to move up. Downward movement of piston 211 causes downward movements of valves 240 and 263. Since the rate of flow into the upper end of cylinder 210 is controlled jointly by valves 205 and 240, the piston 211 will move down at a rate in proportion to 11, the rate of change of speed error. As piston 211 moves down, fluid is forced through pipe 355 into the lower end of cylinder 32I, causing piston 323 to move up. Its rate of movement due to downward movement of piston 211 will be in proporof cylinder 32I to raise the tion to the rate of change of speed error. While this is going on, the valve 263 is moving down to uncover ports 261, 218, thereby connecting the flow from pump P to the lower end of cylinder 32I occasioned by the downward movement of valve 203, will be at a rate in proportion to speed error. Therefore, in consequence of downward movement of piston I52 and downward movement of valve 233, the rate of flow of pressure fluid into the lower end of cylinder 32I will be in proportion to speed error and to the rate of change of speed error. Therefore throttle valve 20 will move up in a valve body 2| at a rate in proportion to speed error and to the rate of change of speed error in order to permit a greater flow (indicated by arrows 22 and 23) of operating medium to the prime mover whereby the governed speed will be attained in the minimum time and the valves 205, 240 and 263 will be returned to equilibrium status.

In the event of over-speed error, valve 205 moves up to uncover port 248 of valve 240, thereby connecting the upper end of cylinder 210 with drain through pipe 321, port 248 and a drain hole 240a of valve 240. Since the flow from the upper end of cylinder 210 is under joint control by valves 205 and 240, this flow to drain will be at a rate in proportion to the rate of change of speed error. The flow of pressure fluid from the upper end of cylinder 210 is produced by upward movement of piston 211 which moves up due to the fact that, when the pressure in the upper end of cylinder 210 is relieved, the pressure in the upper end of cylinder 32I becomes effective to push piston 323 down to displace fluid in the lower end of cylinder 32I, causing fluid to pass through pipe 355 to the lower end of cylinder 210. Therefore, due to the control of port 248 by valves 240 and 205, piston 211 moves down and causes piston 211 to move up an amount in proportion to the amount of speed error. As piston 211 moves up, valve 263 moves up to uncover port 266, thereby connecting pipe 35I with drain. Since the flow rate through port 266 is in proportion to the amount of speed error, some of the fluid in the lower end of cylinder 32I will escape to drain at a rate in proportion to the amount of speed error. Therefore, piston 323 moves down at a rate in proportion to the rate of flow through pipe 355 to the bottom of cylinder 210 which is in proportion to the rate of change of speed error and also through the pipe 35I at a rate which is in pro portion to the amount of speed error. Therefore, piston 323 and valve 20 move down at a rate in proportion to the amount of speed error and to the rate of change of speed error and the fiow of operating medium to the prime mover will be decreased to correct the speed error in a manner such that equilibrium will be established in the minimum time; and the valves 205, 240 and 253 will return to equilibrium status.

The degree of stabilization efiected through movement of piston 211 is determined by the amount of displacement of piston 211 required to move the follow-up valve 240 into position causing its ports 241, 248 to be closed by land 201. Degree of stabilization increases as the amount of displacement of piston 211 for this purpose increases. In other words, if the movement of valve 240 is smaller in proportion to movement of piston 211. the degree of stabilization is greater than when the movement of valve 244 is greater in proportion to movement of piston 211. Therefore the closer pin 28! is to the vertical center line of valve 240 the greater is the degree of stabilization. Adjustment of pin 282 to the right of the position shown in Fig. 12 decreases the degree of stabilization. 4 While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

. 1. An engine governor comprising an hydraulic servo including a first cylinder and piston therein having greater area on one side than on v the other exposed to fluid pressure, a pressure fluid reservoir, a pump having its inlet connected with the reservoir, a duct directly connecting the outlet of the pump with the .first cylinder end in which the piston side of lesser area is exposed whereby said piston side is continually subjected to a substantially constant total pressure to oppose pressures to which the larger area side of the piston is subjected, agoverning member connected with the piston for movement to correct for overspeed or positive speed error when the total pressure on the large area side of the piston is less than the total pressure on the smaller area side of the piston and, vice versa, to correct for under-speed or negative speed error when the total pressure on the larger area side of the piston is greater than the total pressure on the smaller area side of the piston, two ducts connected with the end portion of the cylinder in which the piston sideof larger area is exposed, a second cylinder, a piston movable therein, said cylinder being connected at one end with one of said ducts, means for connecting the other end of the second cylinder either with the pump outlet or with the reservoir or for blocking flow into or out of said other end of the second cylinder and including two cooperating valves, an engine speed responsive device for controlling one of the valves, a mechanism operated by the second piston for operating the other of said valves as a follow-up valve, means for connecting the other of said ducts either with the pump outlet or with the reservoir or for blocking flow into or out of said other duct and including a third valve and means under control by the speed responsive device for positioning the third valve.

2. A governor according to claim 1 in which one of the two cooperating valves is a spool valve operated directly by the speed responsive device and the other of said valves is a sleeve valve within which the spool valve is slidable and which provides a passage to the reservoir and a port communicating with the pump outlet and a port 8 for connecting the said other end of the second cylinder either with the first port of the sleeve valve or with its passage to the reservoir, said spool valve havingxa land for controlling the second port of the sleeve valve.

3. A governor according to claim 1 in which means under control by the speed responsive device for positioning the third valve is a mechanism operated by the second piston and including a lever operatively connected with the third valve.

4. A governor according to claim 1 in which one of the two cooperating valves is a spool valve operated directly by the speed responsive device and the other of said valves iswa sleeve valve within which the spool valve is slidable and which provides a passage to the reservoir and a port communicating with the pump outlet and a port for connecting the said other end of the second cylinder either with the first port of the sleeve valve or with its passage to the reservoir, said spool valve having a land for controlling the second port of the sleeve valve and in which the mechanism operated by the second piston includes a lever operatively connected with the second piston and the sleeve valve.

5. A governor according to claim 1 in which one of the two cooperating valves is a spool valve operated directly by the speed responsive device and the other of said valves is a sleeve valve within which the spool valve is slidable and which provides a'passage to the reservoir and a port communicating with the pump outlet and a port for connecting the said other endof the second cylinder either with the first port of the sleeve valve or with its passage to the reservoir, said spool valve having a land for controlling the second port of the sleeve valve and in which the mechanism operated by the second piston includes a lever operatively connected with the second piston and the sleeve valve, and in which means under control by the speed responsive device for positioning the third valve includes a second lever operatively connected with the first lever and with the third valve.

6. A governor according to claim 1 in which one of the two cooperating valves is a spool valve operated directly by the speed responsive device and the other of said valves is a sleeve valve within which the spool valve is slidable and which provides a passage to the reservoir and a port communicating with the pump outlet and a port for connecting the said other end of the second cylinder either with the first port of the sleeve valve or with its passage to the reservoir, said spool valve having a land for controlling the second port of the sleeve valve and in which the mechanism operated by the second piston includes a lever operatively connected with the second piston and the sleeve valve, and in which means are provided for adjusting the fulcrums of said levers.

'1. An engine governor comprising a housing providing a reservoir for hydraulic fluid and having a partition wall separating the interior of the housing into upper and lower chambers, a first cylinder within said wall, a first piston in said cylinder, a first piston rod extending upwardly from the first piston and into the upper chamber, means for connecting the first piston rod with an element to be controlled, a second cylinder within said wall, a second piston within the second cylinder and a second piston rod extending from the second piston downwardly into the lower chamber, a pump within the wall,a

9 rotatable flyweight device supported by the wall in the upper chamber, an engine driven shaft supported by the wall, gearing connecting the shaft with the pump and device, a spool valve having spaced lands and connected for longitudinal movement with the device, a sleeve valve enclosing the spool valve and supported for longitudinal movement by the wall, and providing a passage to the lower chamber and a first port for the intake of pressure fluid and a second port for connecting the upper end of the second cylinder with said passage of the sleeve valve or with the intake port, said second port being controlled by a land of the spool valve, a third spool valve having spaced lands and supported for longitudinal movement by the wall, a fixed sleeve within the wall and enclosing the third valve and having a first port for the intake of pressure fluid and .a' second port for making a connection between the lower end of the first cylinder and either with the first port of the second sleeve or with the reservoir, said second port of the fixed sleeve being controlled by a land of the third valve ducts in the wall respectively for connecting the reservoir and pump in- 2 let, for connecting the pump outletwith the first or intake port of the sleeve valve, with the first or intake port of the fixed sleeve, and with the upper or piston rod end of the first cylinder, for connecting the lower ends of the cylinders, and for connecting the upper end of the second cylinder with the second port of the sleeve valve, and mechanism in the lower chamber for transmitting motion from the second piston rod to the sleeve valve and to the third valve.

8. An engine governor according to claim 7 in which the mechanism last mentioned comprises a first lever having one of its ends connected with the second piston rod, having an intermediate portion operatively connected with the sleeve Number Name Date 7 1,810,627 Standerwick June 16, 1931 1,899,556 Caughey Feb. 28, 1933 1,933,311 Caughey Oct. 31, 1933 1,941,372 Warner Dec. 26, 1933 1,966,225 Standerwick July 10 1934 1,976,659 Dickinson Oct. 9, 1934 2,197,743 Crafts Apr. 16, 1940 2,328,451 Hedman Aug. 31, 1943 2,333,454 Van Nest Nov. 2, 1943 2,358,894 Volet Sept. 26, 1944 FOREIGN PATENTS 40 Number Country Date 7 598,520

valve, a fulcrum for the other end of the lever supported by the housing, and comprises a second fulcrum provided by the housing and a second lever operated by the first lever and operatively connected with the third valve.

9. An engine governor according to claim 7 in which the mechanism last mentioned comprises a first lever having one of its ends connected with the second piston rod, having an intermediate portion operatively connected. with the sleeve valve, a fulcrum for the other end of the lever supported by the housing, and comprises a second fulcrum provided by the housing and a second lever operated by the first lever and operatively connected with the third valve and in which means exterior to the housing are provided for adjusting the position of the fulcrum of the first lever.

CLIFFORD L. MUZZEY.

HOWARD CARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Germany June 12, 1934 

